Some of patients having problems relating to teeth have their teeth which should have been present lost due to the reasons such as removal by an operation for decayed tooth, periodontal disease or the like, natural loss and the like.
If all the teeth are present, an individual tooth is usually supported by adjacent teeth and can fully exert its function.
However, if even one of the teeth which should have been present is missing, supporting bodies of the teeth located on both ends of the missing portion decrease and thus, a force for chewing things in mastication cannot be fully exerted. Moreover, if an individual interdental space is expanded by loss of a tooth, food residues and the like can easily remain in the interdental space and thus, further occurrence of periodontal diseases or decayed teeth progresses.
As a measure against such problems occurring due to missing of a tooth, an operation of an implant on a portion where a missing tooth used to be is widely employed.
An implant is a type of an artificial dental root and is usually formed of a fixture to be embedded in a bone and an abutment which is connected to the fixture and serves as a supporting base. By attaching an artificial tooth on the abutment, the artificial tooth can be installed on a portion where a tooth is missing.
FIG. 8 illustrates a schematic perspective view of a fixture used in a prior-art implant for reference.
A usual method of operation for installing an implant will be described below.
First, gingiva covering a portion where a missing tooth used to be present is separated, a drill hole is drilled in the bone and then, a fixture 300 illustrated in FIG. 8 is embedded in the drill hole.
At a stage when the fixture 300 is installed in the bone, the gingiva of the patient is injured and swollen and thus, return to a healthy state of the gingiva is waited for and then, the abutment and the artificial tooth are mounted on the fixture 300.
An internal cavity 310 is provided in the fixture 300, and by screwing the abutment in this internal cavity 310, the abutment can be fixed to the fixture 300.
However, a certain period is required until the state of the gingiva of the patient becomes stable after the fixture 300 is installed in the bone. Thus, it is likely that a bone fragment, a gingival fragment, blood or the like remains in the internal cavity 310 of the fixture 300 or food residues generated during daily meals and the like collect in the internal cavity 310 of the fixture 300.
In order to eliminate the possibility that the bone fragment, gingival fragment, blood or the like and food residues collect in the internal cavity 310 of the fixture 300, such a measure can be proposed that a professional operator such as a dentist performs cleaning so as to keep the internal cavity 310 in a clean state.
However, a diameter of the internal cavity 310 of the fixture 300 used in an implant is usually very small at approximately 3 mm or less, and there is limitation in keeping the internal cavity 310 in a clean state during an operation of an implant, attachment of a healing cap and an abutment and the like.
On the other hand, there can be a method of embedding the fixture 300 of a type having a lid from the beginning on the internal cavity 310 in the bone.
However, if a lid is provided on the internal cavity 310 having a diameter of approximately 3 mm or less, a work of taking off the lid becomes extremely complicated and the operation takes time and in addition, there is a concern that the gingiva around the fixture 300 of the patient is injured during the work of removing the lid.
Moreover, if a prior-art brush used for polishing of teeth is attached to a high-speed rotating device called a micro-motor having been used for polishing of teeth in order to clean the internal cavity 310 of the fixture 300, it is extremely difficult to insert the prior-art brush into only the internal cavity 310 of the fixture 300, and it is also likely that the gingiva in the vicinity of the fixture 300 of the patient is injured.
On the other hand, a small-diameter resin twisted brush with the purpose of interdental cleaning has been proposed.
However, this small-diameter resin twisted brush is a twisted brush in which helical brush bristles are formed around a shaft member and can be used in the perpendicular direction to the surface of a tooth, but it is difficult to use it in the vertical direction to the bone serving as a base of a tooth, that is, in the vertical direction along the surface of the tooth (Patent Literature 1).
The interdental brush represented by the small-diameter resin twisted brush should be used in the perpendicular direction to the surface of a tooth and its working mechanism is totally different from a brush for cleaning the inside of an implant used in the horizontal direction to the surface of a tooth and cannot be referred to in development of a brush for cleaning the inside of an implant.